The Role of Gamma Knife Surgery in the Treatment of Rare Sellar Neoplasms: A Report of Nine Cases

<b>Introduction:</b> The group of so-called "sellar-region masses" consists of a heterogeneous group of neoplasms and tumor-mimicking lesions, whose differential diagnosis may be challenging due to the overlapping of clinical and radiological features, which can be found both in "common" and "uncommon" lesions. The choice of a correct treatment strategy is still arduous and requires histological analysis. Gamma Knife Radiosurgery (GKRS) has already been reported as a safe and effective treatment in these cases. The objective of this study is to evaluate single-center pre-operative data, post-operative outcomes, and long-term follow-up in patients treated with GKRS for unusual sellar tumors. <b>Methods:</b> We retrospectively identified and analyzed nine patients treated with GKRS from 2004 to 2015, according to a standard protocol. Lesions consist of hypothalamic hamartoma (HH), Rathke's cleft cist (RCC), Langerhans cell histiocytosis (LCH), spindle cell oncocytoma (SCO), choroid plexus papilloma (CPP), and ossifying fibroma (OF). The diagnosis was histologically confirmed in six patients that underwent surgery, while in three patients, diagnosis was based on characteristic clinical and radiological findings (two HH and one RCC). Pre-operative and post-operative data were retrieved from medical archives, and long-term follow-up was obtained through clinical and neuroradiological periodic examination. <b>Results:</b> In our series, all the "rare" sellar lesions treated, had a successful radiographic and clinical response in a medium-long follow-up period. <b>Conclusions:</b> The long-term follow-up results suggest that GKRS is a safe and effective treatment in rare sellar lesions, with very low toxicity. To the best of our knowledge, this report represents the largest series of unusual sellar lesions treated with GKRS in a single high-volume center, suggesting that GKRS might be an effective non-invasive adjuvant treatment option. Further studies and a larger number of patients are needed to confirm if residuals of these rare sellar lesions might regress on their own without treatment or if other non-invasive treatments could be as effective as GKRS.